For many years a charge has had to be paid to park in towns. To be able to leave his car in a parking space, a motorist must prepay an amount corresponding to the selected parking time. In the absence of such payment, the vehicle is illegally parked and the driver is liable to be issued a voucher or a fine by surveillance operatives.
To occupy a parking space that has to be paid for, the user must therefore pay for the right to park at an appropriate payment terminal. Such terminals are more widely known as parking meters or parking voucher dispensers.
The parking meter system consists in a terminal at which a motorist wishing to park must pay an amount corresponding to the required parking time by means of coins, a card, etc. An indicator showing the parking time paid for is then displayed on the terminal. This indicator is progressively repositioned as time passes. This kind of system is simple to monitor because surveillance operatives have only to look at the position of the indicator to determine whether the vehicle occupying the space controlled by the terminal in question is legally parked.
In the case of parking voucher dispensers, the user receives a voucher carrying printed information, and in particular the authorized parking time limit, in exchange for payment for the required parking time, by means of coins, an appropriate payment card, etc. The user must place this voucher so that it is clearly visible through the windshield of his vehicle. The surveillance operatives then check that a voucher is present in a parked car and check the indicated parking time limit.
Whatever type of payment terminal is used (parking meter or parking voucher dispenser), it is important to be able to identify as soon as possible any malfunction of a terminal that may disrupt payment by motorists. A prompt diagnosis means that a maintenance operative may be sent out quickly and limits loss of revenue.
The manufacturers of such terminals have therefore developed many tools for diagnosing the operation of terminals and systems for sending any necessary alarms to a remote management center and/or alerting maintenance operatives directly. Checks carried out include checks on the remaining stock of vouchers, filling of the cash box, jamming of coins in the coin sorter, etc.
However, this approach tends to increase the cost of the terminals by increasing the number of sensors and associated electronic circuits and is still incapable of diagnosing certain malfunctions that are undetectable, such as fraud and vandals blocking the payment orifices, and thereby rendering the apparatus inoperative.
It is difficult to place sensors in all the sensitive areas of an apparatus to detect metallic and non-metallic foreign bodies, solids, liquids, etc.